unist utility to add references to parents on nodes in a tree.

Instead of modifying the original syntax tree, this module returns a wrapper that makes it easier to traverse that tree.

Algorithms that work on regular unist trees are (mostly) guaranteed to work on wrapped trees, and each wrapped node maintains a reference to the node from which it originated.

npm:

npm install unist-util-parents

var u = require('unist-builder')
var parents = require('unist-util-parents')

var tree = u('root', [
  u('leaf', 'leaf 1'),
  u('node', [
    u('leaf', 'leaf 2'),
    u('void'),
    u('node', [
      u('leaf', 'leaf 3'),
      u('node', [u('leaf', 'leaf 4')]),
      u('void'),
      u('leaf', 'leaf 5')
    ])
  ])
])

var wrapped = parents(tree)

// Leaf 4
var node = wrapped.children[1].children[2].children[1].children[0]

var chain = []
while (node) {
  chain.unshift(node.type)
  node = node.parent
}

console.log(chain)

Yields:

[ 'root', 'node', 'node', 'node', 'leaf' ]

Returns a wrapped tree with a proxy that imposes two additional properties on all of its nodes:

• parent — parent link (or null for the root node)
• node — link to the original node

None of these properties are enumerable, and the original tree is not changed. This means you can JSON.stringify the wrapped tree and it is just the same.

wrapped.children returns array of wrapped child nodes, so that any recursive algorithm will work on a wrapped tree just as well.

Remember to access .node before you commit any changes to a node.

• tree (Node) — Tree to wrap

Node — A wrapped node: shallow copy of the given node with non-enumerable references to node and parent, and if tree had children, they are wrapped as well.

• unist-util-visit-parents — Recursively walk over unist nodes, with ancestral information

See contributing.md in syntax-tree/.github for ways to get started. See support.md for ways to get help.

This project has a Code of Conduct. By interacting with this repository, organisation, or community you agree to abide by its terms.

MIT © Eugene Sharygin